In recent years, a wireless power supply system in which a power supply cord or a power transmission cable is not used has been focused as a power supply system that supplies power to a battery mounted on a hybrid vehicle or an electric vehicle. In such a resonance-type power supply system, a pair of resonance coils electromagnetically resonating with one another is provided in a way such that one is installed at a ground surface of power supply equipment and the other is mounted to a vehicle so as to supply power in a non-contact manner from the resonance coil installed on the ground surface of the power supply equipment to the resonance coil mounted to the vehicle. Hereinafter, the one resonance coil installed to the power supply equipment is referred to as a power supply side resonance coil, and the other resonance coil mounted to the vehicle is referred to as a power receiving side resonance coil.
The above-described resonance type power supply system is advantageous in that power may be wirelessly supplied even when there is a certain distance between the power supply side resonance coil and the power receiving side resonance coil. However, there is a concern that a great electromagnetic leakage may be generated around the coils since there is a distance between the power supply side resonance coil and the power receiving side resonance coil.
Therefore, as illustrated in FIGS. 14 and 15, a method is considered in which metallic shield frames 103 and 104 that surround side surfaces of a power supply side resonance coil 101 and a power receiving side resonance coil 102 are provided, and, magnetic bodies 105 and 106 are disposed to each side of the power supply side resonance coil 101 and the power receiving side resonance coil 102, the sides which are separated apart from one another (Patent Literature 1) as a method of preventing such an electromagnetic leakage. However, the method has a problem that it is difficult to prevent the electromagnetic leakage sufficiently in a high-power power supply for a hybrid vehicle or an electric vehicle.
In addition, when the power receiving side resonance coil 102 is mounted to an automobile, there are some cases in which power is supplied in a state where the power supply side resonance coil 101 and the power receiving side resonance coil 102 are misaligned from each other. When power is supplied in such a state, the electromagnetic leakage further increases. Moreover, in the high-power power supply, an eddy current occurs at outer surfaces of the shield frames 103 and 104 due to the influence of the electromagnetic leakage so that an electromagnetic noise is generated therefrom, which is problematic.